Medical sheet

Abstract

The present invention provides a medical sheet having a cell infiltration inhibitory effect, which comprises a nonwoven fabric formed of fibers containing an aliphatic polyester and has a porosity of 50 to 90%. The sheet of the present invention is very useful because it has an excellent nerve protection and / or nerve regeneration promoting effect, protects the nerve by inhibiting the infiltration of inflammatory cells such as macrophages by wrapping around the nerve at the site of peripheral nerve injury, and does not give stimulation that adversely affects the nerve due to the passage of body fluids.

Description

Technical Field

[0001] The present invention relates to a sheet having a cell infiltration inhibitory effect, and further to a medical sheet having a nerve protecting and / or nerve regeneration promoting effect in the treatment of peripheral nerve injury (hereinafter, may be simply referred to as "the present sheet"). Background Art

[0002] When tissue is damaged and inflammation occurs due to trauma, surgery, or disease, pain-inducing substances, pain-enhancing substances, or inflammatory cytokines are released from the damaged site or inflammatory cells, causing spontaneous pain, and further inducing inflammatory reactions through axonal reflexes, and inflammation and pain continue. Depending on the degree of damage, peripheral nerve injuries are divided into (1) cases where the axon is not ruptured and the damage is completely recovered, (2) cases where the axon is ruptured, but the continuity of the Schwann tube and the perineurium is maintained, and the nerve gradually regenerates, and (3) cases where the axon and the perineurium are ruptured and there is no macroscopic continuity, or even if there is, the continuity of the axon is lost due to scarring and spontaneous recovery is impossible. Among them, peripheral nerve injuries that cannot heal by their own recovery force are basically treated by end-to-end nerve suture of the damaged nerve. However, if recovery takes a long time, irreversible changes will occur in the muscle tissue, so it is important to promote the regeneration of nerve axons (nerve regeneration). However, as mentioned above, an inflammatory response is induced at the injury site, and nerve scar formation caused by inflammatory cells such as macrophages is one of the factors that hinder nerve regeneration. Therefore, in the treatment of peripheral nerve injury by nerve regeneration, inhibiting nerve scar formation caused by inflammatory cells is an important therapeutic strategy.

[0003] Patent Document 1 discloses a nerve regeneration sheet made of a biodegradable material for regenerating thinner nerve fibers such as autonomic nerves, but does not describe or suggest inhibiting nerve scar formation caused by inflammatory cells to promote nerve regeneration.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Laid-Open No. 2010-115393 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] The object of the present invention is to provide a medical sheet (this sheet), which is wrapped around or retained around the peripheral nerve injury site in a living body, thereby protecting the nerve from the damaging effects of inflammatory cells, inhibiting nerve scar formation, and promoting nerve regeneration. In addition, in order to enhance the promotion of nerve regeneration, this sheet can appropriately contain drugs, such as drugs with nerve injury therapeutic effects, or drugs with anti-inflammatory effects. This sheet can be formed by a biodegradable non-woven fabric that disappears naturally over time, so there is no need to remove the sheet after application to a living body.

[0009] Solutions for solving problems

[0010] As a result of intensive studies to achieve the object, the present inventors have found that the object can be achieved by the following invention.

[0011] [1] A sheet comprising a nonwoven fabric formed of fibers containing an aliphatic polyester, wherein the porosity of the sheet is 50 to 90%, and the sheet has a cell infiltration inhibitory effect.

[0012] [2] The sheet according to [1], wherein the sheet has a thickness of 30 to 70 μm.

[0013] [3] The sheet according to [1] or [2], wherein the weight of the sheet is 0.5 to 10 mg / cm 2 .

[0014] [4] The sheet according to any one of [1] to [3], wherein the density of the sheet is 100 to 1000 mg / cm 3 .

[0015] [5] The sheet according to any one of [1] to [4], wherein the fibers have an average fiber diameter of 300 to 1500 nm.

[0016] [6] The sheet according to any one of [1] to [5], wherein the aliphatic polyester contained in the fiber has a molecular weight distribution having local maxima in at least two or more regions of molecular weight.

[0017] [7] The sheet according to [6], wherein at least one of the regions of the molecular weight is a region where the number average molecular weight before sterilization treatment is 1000 to 7000.

[0018] [8] The sheet according to [6] or [7], wherein at least one of the regions of the molecular weight is a region where the number average molecular weight before sterilization treatment is 40,000 to 150,000.

[0019] [9] The sheet according to [6] or [7], wherein at least one of the regions of the molecular weight is a region where the number average molecular weight before sterilization treatment is 50,000 to 140,000.

[0020]

[10] The sheet according to any one of [6] to [9], wherein the range of the molecular weight is at least two regions of a range of 1,000 to 7,000 and a range of 40,000 to 150,000 number average molecular weight before sterilization.

[0021]

[11] The sheet according to any one of [6] to [9], wherein the range of the molecular weight is at least two regions of a range of 1,000 to 7,000 and a range of 50,000 to 140,000 number average molecular weight before sterilization.

[0022]

[12] A sheet according to any one of [6] to

[11] , wherein when the aliphatic polyester having a maximum value on the lowest molecular weight side among the aliphatic polyesters contained in the fibers forming the nonwoven fabric is defined as a low molecular weight component, and the aliphatic polyester having a maximum value on the highest molecular weight side among the aliphatic polyesters contained in the fibers forming the nonwoven fabric is defined as a high molecular weight component, the mass ratio of the content of the low molecular weight component in the nonwoven fabric to the sum of the content of the low molecular weight component and the content of the high molecular weight component is greater than or equal to 0.01 and less than or equal to 0.3.

[0023]

[13] A sheet according to any one of [6] to

[11] , wherein when the aliphatic polyester having a maximum value on the lowest molecular weight side among the aliphatic polyesters contained in the fibers forming the nonwoven fabric is defined as a low molecular weight component, and the aliphatic polyester having a maximum value on the highest molecular weight side among the aliphatic polyesters contained in the fibers forming the nonwoven fabric is defined as a high molecular weight component, the mass ratio of the content of the low molecular weight component in the nonwoven fabric to the sum of the content of the low molecular weight component and the content of the high molecular weight component is greater than or equal to 0.02 and less than or equal to 0.2.

[0024]

[14] The sheet according to any one of [1] to

[13] , wherein the aliphatic polyester is biodegradable.

[0025]

[15] The sheet according to

[14] , wherein the biodegradable aliphatic polyester is at least one selected from the group consisting of polycaprolactone, polycaprolactone diol, polylactic acid, polyglycolic acid, and copolymers thereof.

[0026]

[16] The sheet according to

[14] or

[15] , wherein the biodegradable aliphatic polyester is at least one selected from the group consisting of polycaprolactone, polycaprolactone diol, and copolymers thereof.

[0027]

[17] The sheet according to any one of [1] to

[16] , wherein the cells are inflammatory cells.

[0028]

[18] The sheet according to any one of [1] to

[17] , wherein the sheet further has a neuroprotective and / or neuroregeneration promoting effect.

[0029]

[19] The sheet according to

[18] , wherein the neuroprotective and / or neuroregeneration promoting effect is due to the inhibition of nerve scar formation.

[0030]

[20] The sheet according to any one of [1] to

[19] , wherein the sheet further contains a drug.

[0031]

[21] The sheet according to

[20] , wherein the drug is a therapeutic agent for nerve damage.

[0032]

[22] The sheet according to

[21] , wherein the therapeutic agent for nerve damage is vitamin B12.

[0033]

[23] The sheet according to

[22] , wherein the vitamin B12 is methylcobalamin.

[0034]

[24] The sheet according to

[22] or

[23] , wherein the content of vitamin B12 is 2 Sheet 0.005~0.5mg.

[0035]

[25] The sheet according to

[22] or

[23] above, wherein the content of vitamin B12 is 2 Sheet 0.0075~0.4mg.

[0036]

[26] The sheet according to any one of [1] to

[25] , wherein the sheet is used by being implanted in the vicinity of a nerve injury site in a living body.

[0037]

[27] The sheet according to any one of [1] to

[25] , wherein the sheet is used by wrapping around a nerve at a nerve injury site in a living body.

[0038]

[28] The sheet according to

[26] or

[27] , wherein the living body is a human.

[0039]

[29] The sheet according to any one of [1] to

[28] , wherein the sheet has been sterilized.

[0040]

[30] The sheet according to

[29] , wherein the sterilization treatment is electron beam sterilization or EOG sterilization.

[0041] Effects of the Invention

[0042] According to the present invention, a sheet having excellent nerve protection and / or nerve regeneration promoting effects can be provided, which protects the nerves by wrapping around the nerves at the site of peripheral nerve damage and inhibiting the infiltration of inflammatory cells such as macrophages, and does not provide stimulation that has an adverse effect on the nerves due to the passage of body fluids. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] [ Figure 1 ] is a scanning electron micrograph of sheets A and B produced in Example 1. DETAILED DESCRIPTION

[0044] The present invention provides a sheet (the present sheet) comprising a nonwoven fabric formed of fibers containing aliphatic polyesters, and having a porosity of 50 to 90%, which is preferred for exhibiting a cell infiltration inhibitory effect. Due to the structure of the nonwoven fabric, etc., the present sheet has a neuroprotective and / or nerve regeneration promoting effect by allowing body fluids to penetrate but inhibiting cell infiltration. In addition, the present sheet can be made of a nonwoven fabric formed of fibers containing biodegradable aliphatic polyesters, and the aliphatic polyester has a molecular weight distribution with a maximum value present in at least two or more molecular weight regions. The sheet has excellent biodegradability, and the period of the neuroprotective and / or nerve regeneration promoting effect of the sheet can be adjusted to an appropriate period. In the nonwoven fabric according to the present sheet, the fibers are oriented in one direction or randomly in the fiber sheet, net or mat, and do not include paper, woven fabrics, knitted fabrics, tufts and felts. In addition, the individual fibers can be in a stacked form, or in a form of interweaving (entangled), fused or bonded, or a combination of these forms. Furthermore, by incorporating a drug such as a therapeutic agent for nerve damage into the present sheet, the effect of promoting nerve protection and / or nerve regeneration can be further enhanced.

[0045] Examples of the aliphatic polyester contained in the fibers forming the nonwoven fabric according to the present sheet include biodegradable aliphatic polyesters such as polycaprolactone, polylactic acid, polyglycolic acid, polyglyceric acid, polyhydroxyalkanoic acid, polybutylene succinate, copolymers thereof, or derivatives thereof, and preferably include polycaprolactone or a copolymer thereof, polylactic acid or a copolymer thereof, polyglycolic acid or a copolymer thereof, or a mixture thereof.

[0046] In addition, as the aliphatic polyester, those using any polymerization initiator such as diol, hydroxy acid, dicarboxylic acid, etc. can also be used, and specific examples thereof include poly (ε-caprolactone) diol (which may be simply referred to as "polycaprolactone diol") using propylene glycol or diethylene glycol as a polymerization initiator, and polylactic acid dicarboxylic acid using fumaric acid as a polymerization initiator, etc. Examples of the aliphatic polyester contained in the fiber forming the nonwoven fabric according to the present sheet more preferably include polycaprolactone, polycaprolactone diol, or a copolymer thereof, or a mixture thereof.

[0047] Further, the fibers forming the nonwoven fabric according to the present sheet only need to contain at least one or more of the aliphatic polyesters, and may contain copolymers of biodegradable polymers other than the aliphatic polyesters and the aliphatic polyesters. In addition, the fibers forming the nonwoven fabric according to the present sheet may contain copolymers containing multiple aliphatic polyesters. In the case of copolymers, the copolymerization form may be any one of block copolymerization, random copolymerization, alternating copolymerization, and graft copolymerization.

[0048] The aliphatic polyester may have at least two or more maximum values ​​in the molecular weight distribution. In this case, each maximum value (peak of the molecular weight distribution) has a different value, and has at least two peaks of a peak on the lowest molecular weight side (hereinafter, also referred to as "peak X") and a peak on the highest molecular weight side (hereinafter, also referred to as "peak Y"). The molecular weight distribution of the aliphatic polyester forming the fiber of the nonwoven fabric according to the present sheet can be obtained by comparing with standard polyethylene glycol / polyethylene oxide using gel permeation chromatography (GPC) with THF as a mobile phase.

[0049] It is speculated that the relatively low molecular weight component (hereinafter, also referred to as "low molecular weight component") constituting the peak X of the aliphatic polyester lowers the melting temperature of the aliphatic polyester fiber and / or lowers the crystallinity of the aliphatic polyester fiber. Accordingly, the present sheet has excellent biodegradability. In addition, since part of the low molecular weight component is located on the fiber surface, fiber decomposition is easily caused from the surface. On the other hand, the relatively high molecular weight component (hereinafter, also referred to as "high molecular weight component") constituting the peak Y of the aliphatic polyester improves the mechanical properties of the nonwoven fabric, so the present sheet has excellent structural stability.

[0050] When the fiber forming the nonwoven fabric according to the present sheet is made of an aliphatic polyester containing a low molecular weight component and a high molecular weight component, i.e., an aliphatic polyester having at least two maximum values ​​in the molecular weight distribution, the aliphatic polyester of the low molecular weight component and the aliphatic polyester of the high molecular weight component may be generally mixed. In this case, in terms of affinity, it is preferred to use the same kind of aliphatic polyester of the low molecular weight component and aliphatic polyester of the high molecular weight component. Among the above aliphatic polyesters, polycaprolactone diol synthesized using diol as a polymerization initiator can be considered to be the same kind as polycaprolactone.

[0051] The molecular weight of the low molecular weight component is not particularly limited, and the number average molecular weight before sterilization is, for example, 1000 to 7000, preferably 2000 to 6000, and more preferably 2500 to 5000. In addition, the weight average molecular weight before sterilization is, for example, 1500 to 12000, preferably 3000 to 10000, and more preferably 4000 to 9000.

[0052] On the other hand, the molecular weight of the high molecular weight component is not particularly limited, and the number average molecular weight before sterilization is, for example, 40,000 to 150,000, preferably 50,000 to 140,000, and more preferably 60,000 to 130,000. In addition, the weight average molecular weight before sterilization is, for example, 60,000 to 260,000, preferably 80,000 to 240,000, and more preferably 100,000 to 220,000.

[0053] The present sheet is preferably sterilized for its intended use, but it has been found that the molecular weight of the aliphatic polyester used as the raw material for manufacturing the present sheet is reduced by electron beam sterilization. That is, when the molecular weight of the aliphatic polyester before sterilization is compared with the molecular weight of the aliphatic polyester after sterilization, when the electron beam irradiation dose is 20 to 30 kGy, it has been confirmed that the molecular weight of the low molecular weight component is reduced by about 5 to 10% and the high molecular weight component is reduced by about 15 to 30%, and it has been found that the molecular weight of the high molecular weight component is particularly significantly reduced. The degree of molecular weight reduction of the aliphatic polyester is about 5 to 10% higher than the weight average molecular weight when expressed as the number average molecular weight. Therefore, it is believed that the molecular weight of peaks X and Y of the present sheet after sterilization treatment is reduced by about 5 to 10% in peak X and by about 15 to 30% in peak Y compared with the molecular weight before sterilization treatment.

[0054] The molecular weight of the aliphatic polyester contained in the fiber forming the nonwoven fabric according to the present sheet can be appropriately set to a preferred value according to the degree of nerve damage applied by the present sheet, the period until disappearance after application, the type of drugs such as therapeutic agents for nerve damage when containing drugs, and the release rate and release period of the drugs. Even when blending low molecular weight components and high molecular weight components as aliphatic polyesters, the molecular weight of each component and its blending ratio are not particularly limited, and can be appropriately changed according to the use of the present sheet described later and the drugs to be contained in the present sheet. By implanting the present sheet into the peripheral nerve injury site and its peripheral part or wrapping the present sheet around the nerve, and, if necessary, controlling the release period of the drug from the present sheet or until the present sheet is biodegraded and disappears, the neuroprotection and regeneration effect of the present sheet can be more accurately demonstrated. In this case, the mass ratio of the content of the low molecular weight component in the nonwoven fabric relative to the content of the low molecular weight component and the content of the high molecular weight component is, for example, 0.01 or more and 0.3 or less, preferably 0.02 or more and 0.2 or less. Furthermore, when the low molecular weight component and the high molecular weight component are within the above ranges, a nonwoven fabric having more excellent uniformity (particularly, uniform fiber diameter) can be obtained.

[0055] The aliphatic polyester may have three or more local maxima in the molecular weight distribution, and the upper limit of the number of local maxima is not particularly limited. Even when there are three or more local maxima, it is preferred that the molecular weights of peak X and peak Y are each within the above range.

[0056] The content of the aliphatic polyester in the fibers of the nonwoven fabric of the present sheet is not particularly limited, but is preferably 0.01 to 100 wt %, more preferably 0.5 to 100 wt %, and further preferably 25 to 100 wt % based on the total weight of the fibers.

[0057] The average fiber diameter of the fibers of the nonwoven fabric according to the present sheet is not particularly limited, but is preferably 300 to 1500 nm, more preferably 400 to 1300 nm, and further preferably 500 to 1000 nm. When the average fiber diameter is 100 nm or more, the present sheet has excellent structural stability, and when the average fiber diameter is 1500 nm or less, the present sheet has excellent flexibility, biodegradability, and cell infiltration inhibition. The average fiber diameter of the fibers of the nonwoven fabric according to the present sheet can be determined by observing the nonwoven fabric using a scanning electron microscope and arithmetically averaging the width of about 10 fibers substantially perpendicular to the length direction.

[0058] The weight (weight per unit area) of the sheet is not particularly limited. However, for example, when the sheet is used for the purpose of treating peripheral nerve damage, the weight of the sheet is preferably 0.5 to 10 mg / cm2 in terms of inhibiting nerve scar formation caused by inflammatory cells, protecting nerves and / or promoting nerve regeneration. 2 , more preferably 0.8 to 5 mg / cm 2 , more preferably 1 to 3 mg / cm 2 .

[0059] The density (weight per unit volume) of the sheet is not particularly limited. However, for example, when the sheet is used for the purpose of treating peripheral nerve damage, the density of the sheet is preferably 100 to 1000 mg / cm2 in terms of inhibiting nerve scar formation caused by inflammatory cells, protecting nerves and / or promoting nerve regeneration. 3 , more preferably 200 to 800 mg / cm 3 , more preferably 250 to 600 mg / cm 3 .

[0060] The thickness of the sheet is not particularly limited. However, for example, when the sheet is used for the purpose of treating peripheral nerve injury, in terms of inhibiting nerve scar formation caused by inflammatory cells, protecting nerves and / or promoting nerve regeneration, and applying to the site of nerve injury, such as wrapping around nerves, the thickness of the sheet is preferably 30 to 70 μm, more preferably 35 to 65 μm, and further preferably 40 to 60 μm. The thickness of the sheet can be determined by measuring the thickness at three points using a micrometer and averaging the measured values.

[0061] For example, when the sheet is used to treat peripheral nerve damage, in terms of inhibiting nerve scar formation caused by inflammatory cells, protecting nerves and / or promoting nerve regeneration, the porosity of the sheet is preferably 50 to 90%, more preferably 60 to 80%, and further preferably 65 to 75%. 2 ) and the thickness of the sheet and the specific gravity of the aliphatic polyester (e.g., polycaprolactone is 1.15 g / cm 3 )The porosity of the sheet is calculated by the following formula.

[0062] Porosity (%) = (thickness - per 1cm 2 Weight / Specific gravity of aliphatic polyester) / Thickness×100

[0063] The bending resistance of the sheet material was measured using a commercially available Gurley bending resistance tester according to JIS L1096 A. As a result, since the sheet material is very soft, the bending resistance is less than the minimum reading scale (e.g., 0.2 mN), and the bending resistance cannot be measured. In other words, the sheet material has such high flexibility that the bending resistance cannot be measured. Therefore, for example, the sheet material is easily wrapped around the nerves at the peripheral nerve injury site or is left to cover the site. Even in this case, the sheet material has the advantage of not giving stimulation that adversely affects the nerves and surrounding tissues.

[0064] This sheet may contain components other than those described above, and examples thereof include drugs. In particular, the present invention can provide a sheet containing a therapeutic agent for nerve damage to further enhance the neuroprotective and / or nerve regeneration promoting effect. When the sheet containing the drug is applied as a medical device for indwelling in the living body or inserted into the body, the drug can be released into the living body as the nonwoven fabric decomposes. The drug-containing sheet of the present invention can maintain the shape of the nonwoven fabric in the living body for a desired period, so that the drug is released with its decomposition, and further, after the desired period, the nonwoven fabric can be completely decomposed. The period during which the shape of the nonwoven fabric is maintained in the living body is not particularly limited, but is, for example, a period of 1 to 12 months. The period until the nonwoven fabric is completely decomposed in the living body is, for example, a period of 6 to 24 months. In the case of containing drugs such as therapeutic agents for nerve damage, the period during which the nonwoven fabric maintains its shape in the living body, the period until the nonwoven fabric is completely decomposed in the living body, etc. can be appropriately set according to the degree of nerve damage, the type of drug, the release rate of the drug, and the release period, etc. to design the sheet.

[0065] The drug contained in the present sheet is not particularly limited, but for example, in the case of a therapeutic agent for nerve damage, examples include vitamin B12 (including pharmaceutically permitted salts when a salt is present. The same applies hereinafter.). Vitamin B12 includes cobalamin and its derivatives. More specific examples thereof include methylcobalamin, cyanocobalamin, hydroxocobalamin, sulfitocobalamin, and adenosylcobalamin, and methylcobalamin, cyanocobalamin and hydroxocobalamin are preferred, and methylcobalamin is more preferred. The content of vitamin B12 is not particularly limited, but for example, it is preferably 100% per 1 cm 2The present sheet material is 0.005-0.5 mg, more preferably 0.0075-0.4 mg, and further preferably 0.01-0.3 mg. In addition, the content of vitamin B12 relative to 100% by weight of the present sheet material is not particularly limited, but for example, it is preferably 0.3-30% by weight, more preferably 0.45-24% by weight, and further preferably 0.6-18% by weight. The drug may be contained alone or in combination of two or more thereof. The content of the drug contained in the present sheet material may be appropriately set according to the degree of the disease to be treated, the type of drug, the period of release, and the like.

[0066] For example, this sheet material can be used by implanting the nerve injury site and its peripheral part or winding around the nerve. As mentioned above, since this sheet material is formed to have flexibility, the use mode can be appropriately selected. Specifically, for example, when this sheet material is applied to a patient with nerve injury due to surgery, it is preferred to peel off the periphery of the nerve in the affected area to expose the nerve, and then this sheet material is wound around the nerve or left to cover the nerve. By applying this sheet material to the damaged nerve in this way, inflammatory cells can be suppressed from infiltrating into the nerve tissue to prevent scarring of the nerve tissue due to the destructive action of inflammatory cells, and to promote the protection and / or regeneration of the damaged nerve. After such application, the surrounding tissue is restored and the skin is sutured. This sheet material is formed flexibly, and this sheet material suppresses the infiltration of inflammatory cells, but since the body fluid that keeps the normal state of the organization passes through the sheet material, even if it is left in the nerve injury site, it will not give stimulation that adversely affects the nerve and the surrounding tissue. In this way, this sheet material can be used by winding around the nerve or by implanting the peripheral part of the nerve injury site, and it is not necessary to remove it after the treatment of the injury site. In particular, when the present sheet is applied to a living body and used, it is preferably sterilized. As a sterilization method, it is preferred to select a method that does not decompose the contained drug and does not damage the shape and physical properties of the sheet, and examples thereof include electron beam sterilization and ethylene oxide gas (EOG) sterilization of radiation sterilization methods.

[0067] Because this sheet material has nerve protection and / or nerve regeneration promotion effect, it is very useful, and continuous nerve damage with continuity at the injury site and discontinuous nerve damage whose continuity at the injury site is cut off can be treated. The example of continuous nerve damage includes entrapment neuropathy (the state in which the nerve is compressed by surrounding tissue) such as carpal tunnel syndrome. In addition, this sheet material is also effective for promoting the regeneration of the nerve after nerve suture (direct suture after nerve damage), nerve after neurolysis and nerve implantation (neural transplantation is carried out to defective nerve injury site to provide continuity). Further, this sheet material, by being used alone or in combination with artificial nerves, also has the effect of promoting the treatment of discontinuous nerve damage.

[0068] The manufacturing method of the nonwoven fabric according to this sheet is not particularly limited, and known methods can be used. For example, a solution containing biodegradable aliphatic polyester and desired drugs such as vitamin B12 can be prepared, and the sheet can be manufactured by manufacturing fibers and forming nonwoven fabrics by known methods such as electrospinning, self-assembly or phase separation. For the preparation of solution (raw solution), a suitable solvent can be used. Examples of solvents include trifluoroethanol (TFE), 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), chloroform, and N,N-dimethylformamide (DMF), etc., and these can be used alone or in combination. The solvent used in the raw solution is removed in the spinning step and will not remain in the nonwoven fabric. In addition, various additives can also be used to adjust conductivity and viscosity, etc. The electrospinning method using TFE as a solvent is one of the preferred manufacturing methods because a nonwoven fabric with a more excellent effect of the present invention can be obtained.

[0069] In the electrospinning method, the electrospinning composition is charged by applying a high voltage to produce fibers, and then the fibers are stacked to produce a nonwoven fabric. The method for charging the electrospinning composition is carried out by connecting an electrode connected to a high voltage power supply device to the electrospinning composition itself or a container and applying a voltage. The applied voltage is not particularly limited, and is, for example, 10 to 50 kV, more preferably 15 to 45 kV, and further preferably 20 to 40 kV. The type of voltage may be direct current or alternating current. The flow rate of the electrospinning composition is not particularly limited, and is, for example, 0.2 to 0.8 mL / h, more preferably 0.3 to 0.7 mL / h, and further preferably 0.4 to 0.6 mL / h. In addition, the size of the needle is not particularly limited, and is, for example, 24 to 30 G, more preferably 25 to 29 G, and further preferably 26 to 28 G. Furthermore, the distance from the needle to the target electrode (spinning distance) is not particularly limited, but is, for example, 5 to 30 cm, more preferably 8 to 25 cm, and even more preferably 10 to 20 cm.

[0070] Example

[0071] Hereinafter, the present invention will be described in detail based on embodiments, but the scope of the present invention should not be interpreted in a limiting manner by the following embodiments. That is, the scope of the present invention is not limited by the above description or the following embodiments, but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0072] Example 1. Production of the sheet

[0073] Polycaprolactone having a number average molecular weight of 101,000 as measured by gel permeation chromatography (average value of n=2) (also referred to as "101kPCL" in this example) and polycaprolactone diol having a number average molecular weight of 3,865 as measured by the same method (average value of n=2) (also referred to as "3.9kPCL diol" in this specification) were prepared.

[0074] 101kPCL and 3.9kPCL diols were dissolved in trifluoroethanol (TFE) at a ratio of (A) 9:1 and (B) 8:2, so that the total concentrations of 101kPCL and 3.9kPCL diols relative to 100% by weight of TFE were (A) 7.2% by weight and (B) 8.1% by weight, respectively, to prepare a composition for electrospinning. In addition, a composition for electrospinning was prepared separately, in which, for example, methylcobalamin, a therapeutic agent for nerve damage, was added as a drug in an amount equivalent to 0.3 to 30% by weight relative to the total of 101kPCL and 3.9kPCL diols. In both cases A and B, per 1 cm 2 The produced sheet has a methylcobalamin content of 0.005 to 0.5 mg, and the methylcobalamin content is 0.3 to 30% by weight relative to 100% by weight of the produced sheet.

[0075] The electrospinning compositions A and B prepared above were spun using an electrospinning apparatus to produce sheets A and B made of nonwoven fabrics. At this time, a needle (27G) was used as an ejector, the distance from the needle to the target electrode was set to 17 cm, the ejection speed was 0.5 mL / h, and the applied voltage was set to 30 kV. As a result of measuring the thickness, weight, and density of the sheets produced, the thickness, weight, and density of the sheets A and B were 30 to 70 μm, 0.5 to 10 mg / cm, respectively. 2 and 100~1000mg / cm 3 Further, when the thickness of sheets A and B is 1 cm 2 When the porosity was calculated based on the formula described in paragraph

[0026] based on the measurement result of the weight of , the porosity of each of the sheets A and B was 50 to 90%.

[0076] Example 2. Scanning electron microscopy observation

[0077] Figure 1] The scanning electron micrographs of sheets A and B manufactured in Example 1 are shown in FIG. In addition, as a result of measuring the diameters of 10 fibers of sheets A and B from the electron micrographs, the fiber diameter of sheet A is 319.2 to 1974.0 nm, and the fiber diameter of sheet B is 336.5 to 1333.0 nm. The average fiber diameter (± standard deviation) is calculated for each. As an example of the results, the average fiber diameter of sheet A is 933.6 (± 457.9) nm, and the average fiber diameter of sheet B is 799.0 (± 328.7) nm.

[0078] Example 3. Cell Infiltration Inhibition Assay

[0079] For three sheets having different production numbers (production batches) (production number 1, production number 2, production number 3), respectively, sheet A manufactured in Example 1 and sheet A' obtained by immersing the sheet in phosphate buffered saline (PBS) for one month (hereinafter, also referred to as "PBS-impregnated sheet"), the cell infiltration inhibitory ability was confirmed by the following test method.

[0080] (1) Preparation of PBS-impregnated sheet (sheet A')

[0081] Under light-shielding conditions, immerse each sheet in 100 mL PBS at 37°C ± 1°C (with the resulting humidity) for 1 month. Place the total amount of the immersed sheet and PBS immersion solution in the upper filter portion of the filter system (serial number: 430770, Corning Incorporated) and gently filter. Gently filter and clean the inner wall surface of the upper filter system and the sheet on the filter with about 10 mL of sterile purified water (Japanese Pharmacopoeia) 10 times. Place the sheet on sterilized filter paper and dry it naturally in a clean bench for more than 12 hours.

[0082] (2) Preparation of inserts

[0083] The membrane (Production No.: CBA-102 (Part No. 10201), CELLBIOLABS, INC.) attached to the cell culture insert was peeled off. Next, a sheet A or a sheet A' cut into a circle with a diameter of about 2.5 cm was attached to cover the bottom surface to the side surface of the insert using white vaseline (KENEI Pharmaceutical Co., Ltd.), and the side surface of the insert was wrapped with a sealing film (Parafilm) to fix each sheet. Similarly, three inserts with a membrane having a pore size of 0.4 μm were prepared as a negative control, and three inserts with a membrane having a pore size of 5 μm were prepared as a positive control.

[0084] (3) Cell invasion inhibition assay

[0085] A cell suspension was prepared using serum-free medium (RPMI 1640, 10% fetal bovine serum (FBS)) so that the concentration of THP-1 cells (human monocyte-derived cell line, American Type Culture Collection) was 1.5×10 6 Cells / mL. 500 μL of culture medium (RPMI 1640, 10% FBS) containing fetal bovine serum (chemokine) was placed in each well of a 24-well plate, each insert (3 inserts each) was stacked thereon, and 100 μL of cell suspension was added to the upper layer of each insert. In each of sheet A, sheet A', negative control and positive control, each prepared by adding serum-free culture medium to the upper layer of the insert was used as a blank control. These 24-well plates were shielded from light with aluminum foil when necessary, placed in a carbon dioxide gas incubator (37.0°C, 5% CO2), and cultured for 18 hours.

[0086] After culture, observe the lower layer of each insert using a phase contrast microscope. Remove the cell suspension on the upper surface of the insert, and transfer the insert to a new 24-well plate containing 400 μL of cell detachment solution, incubate for 30 minutes at 37.0°C and 5% CO2, and then suspend the cells attached to the lower surface of the insert. Next, add 400 μL of culture medium containing invasive cells remaining in the plate after culture to the wells from which the inserts were removed and mix. Transfer 180 μL of the mixed solution per well to a 96-well plate, and add 60 μL of the prepared 4×Lysis Buffer / Cyquant GR Dye mixed solution (Cyquant GR Dye: 4×Lysis Buffer=1:74) to each well, and let the plate stand at room temperature for 20 minutes under light-shielding conditions. After standing, the fluorescence intensity of the mixed solution in each well was measured using a fluorescence microplate reader (SpectraMax Gemini XPS, Molecular Devices Japan KK) under the condition of excitation / luminescence = 480 / 520, and the number of cells in each of sheet A, sheet A', negative control and positive control was calculated. After the cell infiltration inhibition test, an appropriate amount of 0.1% methylene blue solution was dropped onto the upper layer of the insert to which the sheet was attached, and it was confirmed that the methylene blue solution did not leak from the side surface of the insert. As an example of the results, the number of infiltrating cells in sheet A is shown in Table 1, and the number of infiltrating cells in sheet A' is shown in Table 2.

[0087] [Table 1]

[0088]

[0089] [Table 2]

[0090]

[0091] As can be seen from Table 1, for the unused sheet A, as in the negative control, cell penetration is inhibited. In addition, as can be seen from Table 2, for the sheet A' immersed in PBS, which is assumed to be implanted in a living body for 1 month, there is a tendency to slightly penetrate cells compared to the negative control, but since the number of infiltrated cells is less than 1 / 10 compared to the positive control, it is confirmed that both sheet A and sheet A' inhibit cell penetration. From the above results, it is confirmed that when this sheet is applied to the nerves of the peripheral nerve injury site and its peripheral part, by inhibiting the infiltration of inflammatory cells such as macrophages, this sheet has the usefulness of preventing nerve scar formation and showing neuroprotection and / or nerve regeneration promotion. In addition, by comparing the results of sheet A and sheet A', it is confirmed that the infiltration inhibitory effect of this sheet on inflammatory cells is confirmed, and the strongest effect is confirmed in the initial stage of this sheet being applied to the living body, and it is confirmed that with the progress of biodegradability, the effect tends to gradually weaken.

[0092] Example 4. Body fluid permeability test

[0093] The body fluid permeability of the present sheets of production numbers 1 to 3 (the same sheets as sheet A of Example 3) was confirmed by the following test method for measuring the permeability of an albumin solution.

[0094] In the same manner as in Example 3, the present sheet of each production number and a membrane with a pore size of 0.4 μm as a comparative sample are attached to an insert (1 each). 500 μL of Dulbecco's phosphate buffer (DPBS) is placed in each well of a 24-well plate, and each insert is covered thereon. 100 μL of a 3% human serum albumin (HSA) solution prepared using DPBS is added from the upper layer of the insert. The 24-well plate is shielded from light with aluminum foil as necessary, placed in a carbon dioxide gas incubator (37.0°C, 5% CO2), and allowed to stand for 18 hours. After standing, the solution in the lower layer of each insert is collected as a sample solution. In addition, for each sample (sheets of production numbers 1 to 3 and comparative samples), a sample is prepared by adding 100 μL of DPBS to the upper layer of the insert, the sample is allowed to stand under the same conditions, and then the solution in the lower layer of the insert is used as a blank solution. In addition, a solution obtained by adding 500 μL of DPBS and 100 μL of 3% HSA solution to a 24-well plate without covering the insert and leaving the plate to stand under the same conditions was used as a target solution (assuming that it was a sample solution when HSA was equilibrated inside and outside the insert).

[0095] For each of the standard solution (each concentration dilution solution of the HSA standard stock solution), sample solution, blank solution and target solution, colorimetric quantification was performed using the BCA protein assay kit (Thermo Fisher Scientific), the absorbance of the standard solution was used to prepare a calibration curve, and the protein concentration in the measurement solution was calculated (the average value of n=2). After the test, an appropriate amount of 0.1% methylene blue solution was dropped on the upper layer of the insert to which the sheet was attached, and it was confirmed that the methylene blue solution did not leak from the side of the insert. As an example of the results, the HSA concentrations of the sample solution and the target solution are shown in Table 3. The result of the HSA concentration of the blank solution in each sample was equal to or less than the lower limit of quantification (25 μg / mL).

[0096] [Table 3]

[0097] HSA concentration (μg / mL) Production No. 1 3895 Production No. 2 3819 Production No. 3 3945 Comparison sample 2162 Control solution 4320

[0098] As can be seen from Table 3, since the HSA concentration of the sample solution of the present sheet material of production numbers 1 to 3 is higher than the HSA concentration of the sample solution of the reference sample, it is confirmed that the present sheet material tends to permeate more HSA than the reference sample. In addition, since there is no significant difference between the HSA concentration of the sample solution of the present sheet material and the HSA concentration of the control solution, it is confirmed that the permeability of HSA hardly changes with the presence or absence of the present sheet material. From the above results, it has been confirmed that the present sheet material fully permeates body fluids in a living body, and therefore has the usefulness of not giving stimulation that adversely affects nerves in nerve protection and / or nerve regeneration promotion.

Claims

1. Use of a nonwoven fabric formed of fibers containing a biodegradable aliphatic polyester in the preparation of a sheet having a porosity of 50 to 75% and having an inflammatory cell infiltration inhibitory effect for use in nerve protection and / or nerve regeneration promotion, wherein the nerve protection and / or nerve regeneration promotion effect is due to the inhibition of nerve scar formation, The aliphatic polyester contained in the fiber has a molecular weight distribution with local maxima in at least two or more regions of molecular weight, and when the aliphatic polyester having a local maxima on the lowest molecular weight side among the aliphatic polyester contained in the fiber forming the nonwoven fabric is defined as a low molecular weight component, and the aliphatic polyester having a local maxima on the highest molecular weight side among the aliphatic polyester contained in the fiber forming the nonwoven fabric is defined as a high molecular weight component, the mass ratio of the content of the low molecular weight component in the nonwoven fabric to the sum of the content of the low molecular weight component and the content of the high molecular weight component is greater than or equal to 0.01 and less than or equal to 0.3, and the molecular weight region is at least two regions of a region of number average molecular weight of 1,000 to 7,000 and a region of 40,000 to 150,000 before sterilization treatment.

2. The use according to claim 1, wherein the thickness of the sheet is 30 to 70 μm.

3. The use according to claim 1, wherein the weight of the sheet is 0.5 to 10 mg / cm 2 .

4. The use according to claim 1, wherein the density of the sheet is 100 to 1000 mg / cm 3 .

5. The use according to claim 1, wherein the fibers have an average fiber diameter of 300 to 1500 nm.

6. The use according to claim 1, wherein the molecular weight range is at least two ranges of a range of 1,000 to 7,000 and a range of 50,000 to 140,000 number average molecular weight before sterilization.

7. The use according to claim 1, wherein When the aliphatic polyester having a maximum value on the lowest molecular weight side among the aliphatic polyesters contained in the fibers forming the nonwoven fabric is defined as a low molecular weight component, and the aliphatic polyester having a maximum value on the highest molecular weight side among the aliphatic polyesters contained in the fibers forming the nonwoven fabric is defined as a high molecular weight component, the mass ratio of the content of the low molecular weight component to the sum of the content of the low molecular weight component and the content of the high molecular weight component in the nonwoven fabric is 0.02 or more and 0.2 or less.

8. The use according to claim 1, wherein the biodegradable aliphatic polyester is at least one selected from the group consisting of polycaprolactone, polycaprolactone diol, polylactic acid, polyglycolic acid, and copolymers thereof.

9. The use according to claim 1, wherein the biodegradable aliphatic polyester is at least one selected from the group consisting of polycaprolactone, polycaprolactone diol and copolymers thereof.

10. The use according to any one of claims 1 to 9, wherein the sheet further contains a drug. The use according to claim 10 , wherein the drug is a therapeutic agent for nerve damage.

12. The use according to claim 11, wherein the therapeutic agent for nerve damage is vitamin B12.

13. The use according to claim 12, wherein the vitamin B12 is methylcobalamin.

14. The use according to claim 12 or 13, wherein the content of vitamin B12 is 2 Sheet 0.005~0.5mg.

15. The use according to claim 12 or 13, wherein the content of vitamin B12 is 2 Sheet 0.0075~0.4mg.

16. The use according to claim 1, wherein the sheet is used by being implanted in the periphery of a nerve injury site in a living body.

17. The use according to claim 1, wherein the sheet is used by winding around a nerve at a nerve injury site in a living body.

18. The use according to claim 16 or 17, wherein the living body is a human.

19. The use according to claim 1, wherein the sheet is sterilized.

20. The use according to claim 19, wherein the sterilization treatment is electron beam sterilization or EOG sterilization.

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